1. Field of the Invention
In well drilling, with a rotary drilling rig, the drill bit and drilling pipe receive rotary motion from power equipment located on the surface. Below the drilling floor, at the ground surface, an assembly known as a rotating head allows the circulation of various fluids used in the drilling. The present invention relates to a top pot assembly. The top pot assembly allows for rotation of the top pot with a driver, including but not limited to a Kelly driver, or without the Kelly driver.
In well drilling, with a rotary drilling rig, the drill bit and drilling pipe receive rotary motion from power equipment located on the surface. Below the drilling floor, at the ground surface, there is usually an assembly known as a rotating head that allows the circulation of various fluids used in the drilling. Early drilling heads employed a single rubber to divert the flow of drilling fluid away from the rig floor. The rubber was fixedly mounted within the drilling head and the drill string rotated and moved longitudinally through the rubber as the rubber sealed against the string. The action of the drill string caused considerable wear on the rubber requiring frequent replacement. To reduce the abrasive wear, the rubber was rotated with the drill string to maintain sealing contact. However, a drill string typically includes various diameter sections. For example, the drill collars joining sections of drill string have a greater diameter than the drill pipe itself. Thus, the rubber was sized to maintain sealing contact with the drill pipe or the smallest diameter component which traveled through the drilling head. Because of the different diameters of the drill string, the rubber needed to be rigid enough to withstand the pressures of the drilling fluid yet resilient enough to maintain a seal on the drill collars as the drill collars passed through the drilling head and thereafter return to the original configuration to seal against the smaller diameter drill pipe. The operating cycle of the rubber was directly proportional to the number of drill collars which passed through the single rubber since the rubber would not return to its original sealing diameter.
Drilling heads typically include a stationary body, often referred to as a bowl. The stationary body houses a rotatable spindle, commonly referred to as a bearing assembly. A Kelly drive or top drive unit rotates the rotatable spindle. One or more seals or packing elements, often referred to as stripper packers or stripper rubber assemblies, is carried by the spindle to seal the drilling head.
As modern wells are drilled ever deeper, or into certain geological formations, very high temperatures and pressures may be encountered on the surface at the drilling head. These rigorous drilling conditions pose increased risks to rig personnel from accidental scalding, burns or contamination by steam, hot water and hot, caustic well fluids. There is a danger of serious injury to rig workers when heavy tools are used to connect a stripper rubber assembly to the drilling head. Accordingly, such a connection should be made quickly and achieve a fluid tight seal.
Rotation of respective rotating components of drilling head is facilitated through a bearing assembly through which the drill string rotates relative to the stationary bowl or housing in which the bearing assembly is seated.
Pressure control is achieved by means of one or more stripper rubber assemblies connected to the bearing assembly and compressively engaged around the drill string to form a seal against the drill string. At least one stripper rubber assembly rotates with the drill string. The rubber presses against the drill string to achieve a fluid-tight seal. Stripper rubber assemblies connect to the drilling head to establish and help maintain a pressure control seal around the drill string.
Present day drilling operations are extremely expensive. An effort to increase the overall efficiency of the drilling operation while minimizing expense requires the essentially continuous operation of the drilling rig. Thus, it is imperative that downtime be minimized to reduce the nonproductive time.
In this regard, there is a need for improved sealing of the rotating head with the rubbers to maximize the useful life of the bearings. There is also a need to minimize nonproductive time through the changing out and replacing the stripper rubber elements.
A primary feature of the top pot assembly of the present invention includes improved sealing of the drill string. The top pot assembly provides a driving head that receives the Kelly driver for rotation of the top pot and inner barrel with the drill string. Further, the top pot assembly simplifies the process of removing and installing the rubber that seals and rotates with the drill string. The present invention also simplifies the process of removing and installing a top rubber. The top pot assembly of the present invention provides simple removal such that a user can easily replace the rubber. Further, the present invention seals on the Drill pipe, Kelly, collars, etc. to prevent debris from escaping the well bore and reduce risk factors involved with rig/drilling operations.
2. Description of the Known Art
Patents and patent applications disclosing information relevant to rotating heads are disclosed below. These patents and patent applications are hereby expressly incorporated by reference in their entirety.
U.S. Pat. No. 4,511,193 (the '193 patent) issued to Geczy on Apr. 16, 1985 teaches a combined radial and thrust bearing assembly for a down-hole drilling assembly to journal a shaft, mounting the drill bit, in a housing. The bearing assembly is used between a down-hole fluid powered motor and a drill bit for drilling oil wells, for example. The bearing assembly includes cooperative pairs of upper and lower inner races located on the shaft for mutual rotation. Each of the inner races includes a pair of interchangeable toroidal tracks. Cooperative pairs of upper and lower outer races are fixed against rotation in the housing. Each outer race has a pair of interchangeable toroidal tracks to selectively cooperate with the tracks of the inner races to define a toroidal channel to receive a number of bearing balls. Spring means are disposed between the upper and lower pairs of outer races and the housing and between the upper and lower pairs of outer races to provide a compliant coupling for the even distribution of radial and upwardly and downwardly directed thrust loads between the races and balls and eventual transfer to the housing. Drilling fluid is circulated through the bearing assembly for cooling and lubrication.
U.S. Pat. No. 5,213,158 (“the '158 patent”) issued to Bailey, et al. on May 25, 1993 teaches a drilling head with dual rotating stripper rubbers designed for high pressure drilling operations ensuring sealing under the extreme conditions of high flow or high pressure wells such as horizontal drilling. The dual stripper rubbers taught by the '158 patent seal on the same diameter yet are manufactured of different materials for different sealing functions. The lower stripper rubber is manufactured from a more rigid, abrasive resistant material to divert the flow from the well. The upper stripper rubber is manufactured of a softer sealing material that will closely conform to the outer diameter of the drill string thereby preventing the flow of fluids through the drilling head.
U.S. Pat. No. 5,647,444 issued to Williams on Jul. 15, 1997 discloses a rotating blowout preventor having at least two rotating stripper rubber seals which provide a continuous seal about a drilling string having drilling string components of varying diameter. A stationary bowl is designed to support a blowout preventor bearing assembly and receives a swivel ball that cooperates with the bowl to self-align the blowout preventor bearing assembly and the swivel ball with respect to the fixed bowl. Chilled water is circulated through the seal boxes of the blowout preventor bearing assembly and liquid such as water is pumped into the bearing assembly annulus between the stripper rubbers to offset well pressure on the stripper rubbers.
U.S. Pat. No. 5,662,181 issued to Williams et al. on Sep. 2, 1997 (“the '181 patent”) teaches a rotating blowout preventor having at least two rotating stripper rubber seals which provide a continuous seal about a kelly or drilling string having drilling string components of varying diameter. A stationary housing of the '181 patent is designed to support a bearing assembly and a clamp cooperates with the housing to secure the bearing assembly in the housing.
U.S. Pat. No. 7,198,098 issued to Williams on Apr. 3, 2007 (“the '098 patent”) teaches a connector system for connecting parts of an apparatus. The '098 patent teaches a first part having one or more bayonet connectors and one or more retention pin receptacles cooperatively mates to a second part having one or more mating bayonet connectors. The second part taught by the '098 patent further provides one or more retention pin bores. The first and second parts taught by the '098 patent assemble to form a bayonet connection such that at least one pin retention bore aligns with at least one retention pin receptacle. The '098 patent teaches that at least one retention pin assembly disposed through the at least one pin retention bore selectively engages the retention pin receptacle to secure the connection of the first part to the second part of the apparatus.
U.S. Publication No. 20090057024 to Williams on Mar. 5, 2009 (“the '024 publication”) teaches an upper stripper rubber canister system that comprises a canister body and a canister body lid. The canister body taught by the '024 publication includes an upper end portion, a lower end portion and a central passage extending therebetween. The central passage taught by the '024 publication is configured for having a stripper rubber assembly disposed therein. The '024 publication teaches an upper end portion of the body that includes a plurality of bayonet connector structures. The canister body lid taught by the '024 publication includes an exterior surface, an upper end portion, a lower end portion and a central passage extending between the end portions thereof. The exterior surface taught by the '024 publication is configured for fitting within the central passage of the canister body. The canister body lid includes a plurality of bayonet connector structures integral with its exterior surface. Each canister body lid bayonet connector structure taught by the '024 publication is configured for being engaged with one of the canister body bayonet connector structures for interlocking the canister body lid with the canister body.